Embed Size (px)
Citation preview
Linked List - I
Abstract Data Type (ADT)
• ADT is a data type whose properties (domain and operations) are specified independently of any particular implementation. – Logical (or ADT) level: abstract view of
the domain and operations. – Implementation level: specific
representation of the structure to hold the data items, and the coding for operations.
4 Basic Kinds of ADT Operations
• Constructor/Destructor – creates/deletes a new instance (object) of an ADT.
• Transformer -- changes the state of one or more of the data values of an instance.
• Observer -- allows us to observe the state of one or more of the data values of an instance without changing them.
• Iterator -- allows us to process all the components in a data structure sequentially.
List
• Linear relationship Each element except the first has a unique predecessor, and each element except the last has a unique successor.
• Length The number of items in a list; the length can vary over time.
Class ShoppingListclass ShoppingList{public :
int LengthIs ( ) const ; void RetrieveItem (int pos) ;void InsertItem (const Item& item, int pos ) ; void RemoveItem (int pos);void DeleteAll ( );
private :int size ; Node *front ;
} ;
Singly Linked List Diagram
Pointer to front node
A B C NULL
Nodes
Data carried in node Pointer to next node
Class Node
A
Item item; Node *link;
class Node {public: Node(Item i){item = i};private: Item item; Node *link;};
Insert an item/node into shopping list?Delete an item/node?
Front Insert Example (1 of 6)
front
A B C
item link item link item link
prev cur pos
0
anItem
D? ?
void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, //ignore prev ptr for the FrontInsert example
*cur; Inserting D at position 0
size
3
Front Insert Example (2 of 6)
front
A B C
item link item link item link
cur pos
0
anItem
D?
assert(pos >= 0 && pos <= size); size++;
size
4
Front Insert Example (3 of 6)
front
A B C
item link item link item link
cur pos
0
anItem
D
if (pos == 0) { // Inserting at the front cur = front;
size
4
Front Insert Example (4 of 6)
front
A B C
item link item link item link
cur pos
0
anItem
D
front = new Node(anItem);
size
4
D
item link
?
Front Insert Example (5 of 6)
front
A B C
item link item link item link
cur pos
0
anItem
D
front->link = cur;
size
4
D
item link
Front Insert Example (6 of 6)
front
A B C
item link item link item link
return; }
size
4
D
item link
Empty Insert Example (1 of 6)
size
cur pos
0
anItem
A?
void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, //ignore prev for EmptyInsert example
*cur; Inserting A at position 0 in empty list
front
0
Empty Insert Example (2 of 6)
size
cur pos
0
anItem
A?
assert(pos >= 0 && pos <= size); size++;
front
1
Empty Insert Example (3 of 6)
size
cur pos
0
anItem
A
if (pos == 0) { // Inserting at the front cur = front;
front
1
Empty Insert Example (4 of 6)
size
cur pos
0
anItem
A
front = new Node(anItem);
front
1
A
item link
?
Empty Insert Example (5 of 6)
size
cur pos
0
anItem
A
front->link = cur;
front
1
A
item link
Empty Insert Example (6 of 6)
size
return; }
front
1
A
item link
Middle Insert Example (1 of 8)void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; Inserting D at position 2
front
A B C
item link item link item link
prev cur pos
2
anItem
D? ?
size
3
Middle Insert Example (2 of 8) assert(pos >= 0 && pos <= size); size++;
front
A B C
item link item link item link
prev cur pos
2
anItem
D? ?
size
4
Middle Insert Example (3 of 8) prev = NULL; cur = front;
front
A B C
item link item link item link
prev cur pos
2
anItem
D
size
4
Middle Insert Example (4 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
First Iteration
front
A B C
item link item link item link
prev cur pos
1
anItem
D
size
4
Middle Insert Example (5 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
Second Iteration
front
A B C
item link item link item link
prev cur pos
0
anItem
D
size
4
Middle Insert Example (6 of 8) prev->link = new Node(anItem);
front
A B C
item link item link item link
prev cur pos
0
anItem
D
size
4
D ?
item link
Middle Insert Example (7 of 8) prev->link->link = cur;
front
A B C
item link item link item link
prev cur pos
0
anItem
D
size
4
D
item link
Middle Insert Example (8 of 8)}
front
A B C
item link item link item link
size
4
D
item link
End Insert Example (1 of 8)void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; Inserting D at position 3
front
A B C
item link item link item link
prev cur pos
3
anItem
D? ?
size
3
End Insert Example (2 of 8) assert(pos >= 0 && pos <= size); size++;
front
A B C
item link item link item link
prev cur pos
3
anItem
D? ?
size
4
End Insert Example (3 of 8) prev = 0; cur = front;
front
A B C
item link item link item link
prev cur pos
3
anItem
D0
size
4
End Insert Example (4 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
First Iteration
front
A B C
item link item link item link
prev cur pos
2
anItem
D
size
4
End Insert Example (5 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
Second Iteration
front
A B C
item link item link item link
prev cur pos
1
anItem
D
size
4
End Insert Example (6 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
Third Iteration
front
A B C
item link item link item link
prev cur pos
0
anItem
D
size
4
End Insert Example (7 of 8) prev->link = new Node(anItem); prev->link->link = cur;
front
A B C
item link item link item link
prev cur pos
0
anItem
D
size
4
D
item link
End Insert Example (8 of 8) }
front
A B C
item link item link item link
size
4
D
item link
void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; assert(pos >= 0 && pos <= size); size++; if (pos == 0) { // Inserting at the front cur = front; front = new Node(anItem); front->link = cur; return; } prev = NULL; cur = front; while (pos > 0) { prev = cur; cur = cur->link; pos--; } prev->link = new Node(anItem); prev->link->link = cur;}
Remove Example (1 of 7)void ShoppingList::remove(int pos) { Node *cur, *prev; Removing at position 1
front
A B C
item link item link item link
prev cur pos
1? ?
size
3
Remove Example (2 of 7) assert(pos >= 0 && pos < size); size--;
front
A B C
item link item link item link
prev cur pos
1? ?
size
2
Remove Example (3 of 7) prev = NULL; cur = front;
front
A B C
item link item link item link
prev cur pos
1
size
2
Remove Example (4 of 7) while (pos > 0) { prev = cur; cur = cur->link; pos--; }
front
A B C
item link item link item link
prev cur pos
0
size
2
First iteration
Delete the node pointed by cur
Remove Example (5 of 7) prev->link = cur->link;
front
A B C
item link item link item link
prev cur pos
0
size
2
Remove Example (6 of 7) delete cur;
front
A B C
item link item link item link
prev cur pos
0
size
2
Remove Example (7 of 7)}
front
A C
item link item link
size
2
Delete All Example (1 of 8)void ShoppingList::deleteAll() { Node *kil;
front
A B C
item link item link item link
kil
?
size
3
Delete All Example (2 of 8) while (front != NULL) { kil = front; front = front->link;
A B C
item link item link item link
kil
frontsize
3
First iteration
Delete All Example (3 of 8) kil->link = NULL; delete kil; }
A B C
item link item link item link
kil
frontsize
3
First iteration
Delete All Example (4 of 8) while (front != NULL) { kil = front; front = front->link;
B C
item link item link
kil
frontsize
3
Second iteration
Delete All Example (5 of 8) kil->link = NULL; delete kil; }
B C
item link item link
kil
frontsize
3
Second iteration
Delete All Example (6 of 8) while (front != NULL) { kil = front; front = front->link;
C
item link
kil
frontsize
3
Third iteration
Delete All Example (7 of 8) kil->link = 0; delete kil; }
C
item link
kil
frontsize
3
Third iteration
0
Delete All Example (8 of 8) size = 0;}
frontsize
0
![L5 - ADTstevenha/cs1020e... · [ CS1020E AY1617S1 Lecture 5 ] Abstract Data Type (ADT) Abstract Data Type (ADT): End result of data abstraction A collection of data together with](https://img.pdfslide.us/doc/110x75/5fa730a7b9c6f16381632206/l5-adt-stevenhacs1020e-cs1020e-ay1617s1-lecture-5-abstract-data-type.jpg)
